Cutting device with changeable cutting depth

ABSTRACT

The invention relates to a cutting device that is provided with a traveling mechanism and a cutting disc that can be rotatably driven by a drive unit. The drive unit and the cutting disc are arranged on a support frame. An undercarriage is movably fixed to the support frame. A relative position can be adjusted between the undercarriage and the support frame by means of an adjustment device. The adjustment device is provided with a coarse adjustment device for adjusting at least two discrete relative positions and a fine adjustment device, which overlaps the effect of the coarse adjustment device in at least one of the discrete relative positions. The fine adjustment device is used for adjusting any relative position in a determined area.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a cutting apparatus, in particular a flat saw,with variable cutting depth.

2. Description of the Related Art

Flat saws—such as, for example, of the type BFS 100 fromWacker-Werke—are used for producing joints in hardened concrete,asphalt, tiles, etc. For this purpose, a diamond-set cutting disc, forexample, is rotationally driven by a drive which is fastened on achassis and thus can easily be moved over the subsurface into which thejoint is to be cut. In the process, the cutting depth, i.e. the depthwith which the cutting disc penetrates into the material to be worked,must be capable of being set with great precision in order to obtain ajoint having a desired cross section.

For this purpose, flat saws having chassis are known in which a frontwheel axis is fastened to a link pivotable relative to the main frame.Since the front wheels are located in the vicinity of the cutting disc,variable plunging of the cutting disc into the material to be cut isobtained by a pivoting movement of the link.

For the adjustment of the link, i.e. for the adjustment of the relativemovement between the main frame and the link, two methods are known onthe one hand, the link can be pivoted relative to the main frame bymeans of a spindle actuated by hand crank. Alternatively, a leverlinkage with latching can be provided.

In the first solution, a relatively high setting accuracy with smalloperating forces can be achieved. However, in order to lift out thecutting disc or plunge it in, numerous turns of the hand crank arenecessary, which increases the working time. The setting and repetitiveaccuracy also depends on the care of the operator, who has to count thenumber of crank turns or take corresponding readings.

The second solution, on account of the discrete latching positions,offers good repetitive accuracy and rapid lifting or plunging of thecutting disc. On account of the predetermined latching positions,however, the setting possibilities are limited, so that joints havingany desired cutting depth cannot be produced. In addition, it is often aproblem for the user in aggravated environmental conditions to find thedesired latching position.

U.S. Pat. No. 4,953,523 discloses a cutting apparatus according to thepreamble of Patent claim 1. Furthermore, this cutting apparatus has aquick-unlocking mechanism which is in engagement with thefine-adjustment device in a releasable manner. When the quick-unlockingmechanism is triggered, the cutting disc is set back into a transportposition by the effect of a pneumatic spring.

OBJECTS AND SUMMARY OF THE INVENTION

The object of the invention is to specify a cutting apparatus in whichthe disadvantages known from the prior art can be avoided.

The object is achieved according to the invention by a cutting apparatushaving the features of Patent claim 1. Advantageous developments of theinvention can be gathered from the dependent claims.

A cutting apparatus according to the invention, in particular a flatsaw, has travel gear for moving the cutting apparatus on a subsurface, acutting disc which can be rotationally driven by a drive, a supportingframe supporting the cutting disc and the drive, an underframe fastenedto the supporting frame in a movable manner and supporting at east atleast one part of the travel gear, and an adjusting arrangement foradjusting the relative position of underframe and supporting frame, theadjusting arrangement having a fine-adjustment device for adjusting anydesired relative positions within a certain region, and the adjustingarrangement having a coarse-adjustment device for adjusting at least twodiscrete relative positions and the fine-adjustment device superimposingthe effect of the coarse-adjustment device in at least one of thediscrete relative positions.

The advantages of the two known arrangements are therefore combined bythe invention. In principle, the cutting-depth setting is effected bythe coarse-adjustment device, which, however, expediently has only twolatching positions, namely a transport position, in which the cuttingdisc does not engage in the material to be cut, and a cutting position.In the cutting position, the effect of the fine-adjustment device comesto bear, by means of which the cutting disc can be set precisely to thedesired cutting depth.

Due to the fact that only two discrete relative positions are possiblefor the coarse-adjustment device, operating errors due to inadvertentsetting of intermediate positions can be avoided. If the fine-adjustmentdevice has been set once merely at the start of an operation, a highrepetitive accuracy of the cutting depth, even if work is interruptedrepeatedly, can be achieved solely by subsequent actuation of thecoarse-adjustment device. Very quick lifting and plunging of the cuttingdisc is possible by means of the coarse-adjustment device.

In a preferred embodiment of the invention, the underframe is pivotablerelative to the supporting frame and supports a part of the travel gear.In particular, the underframe supports a front axle of the travel gear,whereas the supporting frame holds the rear axle of the travel gear. Asa result, the entire frame can be made very light and compact.

If the fine-adjustment device also superimposes the effect of thecoarse-adjustment device in the transport position, the cutting depthcan already be preset by means of a corresponding indicating device orscale without it being necessary for the cutting disc to have penetratedinto the material to be cut.

In a preferred embodiment of the invention, the coarse-adjustment deviceis formed by a latching device and the fine-adjustment device is formedby a spindle device. As a result, the requirements with regard torobustness on the one hand the precision on the other hand can beoptimally fulfilled.

It is especially advantageous in this case if the spindle device carriesthe latching means or latching elements of the latching device, sincethe effects of the coarse- and fine-adjustment devices can readily besuperimposed as a result.

Another advantageous development of the invention has a spring devicewhich prestresses the underframe relative to the supporting frame and bymeans of which the operator can adjust the coarse-adjustment devicebetween the discrete relative positions with relatively small operatingforces.

BRIEF DESCRIPTION OF THE DRAWING

These and further advantages and features of the invention are explainedin more detail below with reference to the accompanying figures, inwhich

FIG. 1 shows a schematic side view of a cutting apparatus according tothe invention; and

FIG. 2 shows an enlarged detail of FIG. 1.

FIG. 1 shows a flat saw in a schematic side view, a drive known per sefor a cutting disc 1 not being shown for the sake of clarity. Thecutting disc 1 is merely shown schematically and is held together withthe drive by the guide carriage 2 (shown in FIG. 1) in such a way thatat least its underside can be brought into contact with the material tobe cut (concrete or asphalt) (not shown).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The guide carriage 2 has a supporting frame 3, on which a link 4 servingas underframe is held on a pivot 5. At its front end, the link 4 carriesa front wheel axle, on which one or more front wheels 6 are held in arotatable manner. Rear wheels 7 are provided on the supporting frame 3in a corresponding manner.

In another embodiment (not shown) of the invention, the underframecarries the entire travel gear, that is to say the front wheels 6 andthe rear wheels 7. The supporting frame is then reduced to an arm or aretaining frame into which the drive with the cutting disc 1 can beinserted. However, the relative mobility between the supporting frameand the underframe is still provided for.

In the exemplary embodiment shown, the link 4 can be moved downwards outof the supporting frame 3 via a lever mechanism.

The lever mechanism comprises a swivel joint 8 which is fastened to thelink 4 and on which a slide 9 acts, the other end of this slide beingconnected via a swivel joint 10 to a lever 12 held on the supportingframe 3 in a pivotable manner at a pivot 11.

This lever mechanism can be pivoted between two end positions. One endposition corresponds to the cutting position shown in FIG. 1, in whichthe link 4 is swung in or the cutting disc 1 is lowered. To reach thesecond end position, namely the transport position, the lever 12 must bepulled rearwards, that is to the right in the figure, by the operator ata handle 13, as a result of which the link 4 is swung out of thesupporting frame 3 about the pivot 5 by the effect of the levermechanism. As a result, the distance critical for the cutting depthbetween a base plane defined by the location surface of the wheels 6, 7and an apex point of the cutting disc 1 decreases, so that the cuttingdisc 1 is lifted out of the material to be cut.

A coarse-adjustment device which comprises a latching device provided inthe vicinity of the handle 13 is provided in order to fix the two endpositions. The latching device has a latching pin 15 (also shown in FIG.2) which can be actuated via a pushbutton 14 on the handle 13. To engagethe latching pin 15, a holding element is provided in each of the twoend positions, namely a latching element 16 for defining the cuttingposition and a latching element 17 for defining the transport position.

For the fine adjustment of the cutting depth, the position of thelatching element 16 for the cutting position can be changed by means ofa spindle 18 serving as a fine-adjustment device. For this purpose, thelatching element 16 is formed on a spindle nut 19 movable on the spindle18.

The spindle 18 is driven via a hand crank 20, so that the operator caneasily set the position of the latching element 16 and thus ultimatelythe position of the link 4 and the cutting depth very precisely.

To release the cutting position, the operator presses the pushbutton 14,as a result of which the latching pin 15 is moved out of the recess onthe latching element 16. The operator can then pull the handle 13 to therear and finally allow the latching pin 15 to engage in the rearlatching element 17 for the transport position.

In the embodiment shown here, the rear latching element 17 is fastenedto the supporting frame 3 in a fixed position. In another embodiment ofthe invention, however, the latching element 17 for the transportposition is likewise fastened to a further spindle nut, so that itsposition likewise changes during rotation of the spindle 18. This makesit possible for the effects caused by the actuation of the spindle bythe operator to be observed by the operator even in the transportposition, that is with the cutting disc 1 lifted. For this purpose, anindicating device can be provided if need be, it being possible for theeffects of the setting by the operator to be read off from thisindicating device by the operator, which considerably facilitates apresetting of the cutting depth.

Another way of facilitating a presetting is by means of a tension spring21 which pivots the link 4 relative to the supporting frame 3 in thedirection of the transport position. At least some of the weight of theguide carriage 2, the cutting disc 1 and the drive is therefore carriedby the tension spring 21, this weight having to be lifted during thetransfer from the cutting position into the transport position.

The set cutting depth can easily be read off if one of the elementswhich can be moved for setting the cutting depth carries a pointer whichis displaceable over a fixed scale arranged, for example, on thesupporting frame 3. The pointer may be arranged, for example, on thelever 12 or the front latching element 16.

We claim:
 1. Cutting apparatus, comprising: a travel gear for moving thecutting apparatus on a subsurface; a cutting disc which can berotationally driven by a drive; a supporting frame supporting the drivewith the cutting disc; an underframe which is fastened to the supportingframe in a movable manner and supports at least one part of the travelgear; and an adjusting arrangement for adjusting the relative positionof the underframe and the supporting frame, the adjusting arrangementhaving a fine-adjustment device for adjusting the desired relativeposition within a certain region; and a coarse-adjustment device foradjusting bi-directionally between at least two discrete relativepositions, wherein the fine-adjustment device superimposes the effect ofthe coarse-adjustment device in at least one of the discrete relativepositions.
 2. The cutting apparatus according to claim 1, wherein theunderframe is pivotable relative to the supporting frame about ahorizontal axis relative to the subsurface and thus can be brought intodifferent vertical positions relative to the subsurface.
 3. The cuttingapparatus according to claim 1, wherein the underframe supports thetravel gear.
 4. The cutting apparatus according to claim 1, wherein thesupporting frame supports a part of the travel gear.
 5. The cuttingapparatus according to claim 1, wherein the coarse-adjustment deviceserves to fix a transport position and a cutting position.
 6. Thecutting apparatus according to claim 5, wherein the fine-adjustmentdevice is effective at least in the cutting position.
 7. The cuttingapparatus according to claim 1, wherein the coarse-adjustment device hasa latching device.
 8. The cutting apparatus according to claim 1,wherein the fine-adjustment device has a spindle device.
 9. The cuttingapparatus according to claim 7, wherein the fine-adjustment device has aspindle device that carries at least one latching element of thelatching device.
 10. The cutting apparatus according to claim 1, whereinthe position of the underframe is prestressed relative to the supportingframe by a spring device.
 11. A cutting apparatus comprising: a travelgear for moving the cutting apparatus on a subsurface; a cutting discwhich can be rotationally driven by a drive; a supporting framesupporting the drive with the cutting disc; an underframe which isfastened to the supporting frame in a movable manner and supports atleast one part of the travel gear; and an adjusting arrangement foradjusting the relative position of the underframe and the supportingframe, the adjusting arrangement having: a coarse-adjustment deviceconfigured to selectively fix the relative position in a transportposition and a cutting position; and a fine-adjustment device configuredto adjust the selectively fixed relative position within a certainregion; wherein the fine-adjustment device superimposes the effect ofthe coarse-adjustment device in at least one of the transport positionand the cutting position.
 12. The cutting apparatus according to claim11, wherein the cutting apparatus comprises a flat saw.
 13. A cuttingapparatus comprising: a travel gear for moving the cutting apparatus ona subsurface; a cutting disc which can be rotationally driven by adrive; a supporting frame supporting the drive with the cutting disc; anunderframe which is fastened to the supporting frame in a movable mannerand supports at least one part of the travel gear; and an adjustingarrangement for adjusting the relative position of the underframe andthe supporting frame, the adjusting arrangement having: acoarse-adjustment device configured to selectively fix the relativeposition in a transport position and a cutting position; and afine-adjustment device configured to adjust the selectively fixedrelative position within a certain region; wherein the fine-adjustmentdevice superimposes the effect of the coarse-adjustment device in atleast one of the transport position and the cutting position.
 14. Thecutting apparatus according to claim 13, wherein the cutting apparatuscomprises a flat saw.
 15. A method comprising: providing a cuttingapparatus having 1) a supporting frame supporting a cutting disc whichcan be rotationally driven by a drive and 2) an underframe which isfastened to the supporting frame in a movable manner and which supportsat least one part of a travel gear for moving a cutting apparatus on asubsurface; selectively adjusting a cutting depth of the cuttingapparatus by: selectively operating a coarse-adjustment device to movethe underframe and supporting frame relative to one another between atransport position in which the cutting disc is spaced from a surface tobe cut and a discrete cutting position in which the cutting disc engagesand cuts the surface to be cut, the coarse-adjustment device beingoperable to relatively move the underframe and supporting framebi-directionally between the transport position and the cuttingposition, and selectively operating a fine-adjustment device to effectadditional relative movement between the underframe and the supportingframe, wherein the effects of the fine-adjustment device aresuperimposed on the effects of the coarse-adjustment device in at leastone of the transport position and the cutting position.
 16. The methodof claim 15, further comprising latching the coarse-adjustment device ina selected one of the transport position and the cutting position aftereach coarse adjustment.
 17. The method of claim 15, further comprisingprestressing the position of the underframe relative to the supportingframe.
 18. The method of claim 15, further comprising presetting acutting depth of the cutting disc prior to the cutting disc penetratingthe subsurface.